Me and my bf are polar opposite on some minor things like I love horrors, he hates them. I'm social, he isn't. I like exercise, he hates it. I like going out, he prefers staying in. Those things are fine to be different on but when it comes to the major things in life like we both feel the same about marriage, kids etc I think that is essential to agree on and one thing you definitely can't be opposite on.

(Original post by Onde)
In terms of the Big Five personality scale, the best relationships are between those who both have higher levels of agreeableness and conscientiousness compared to average, and lower levels of neuroticism.

In terms of Jungian personality types, it has been said that (not backed by any actual empirical research):
introverted intuition types pair well with extroverted sensing types
introverted feeling types pair well with extroverted thinking types
introverted sensing types pair well with extroverted intuition types
introverted thinking types pair well with extroverted feeling types

According to OKCupid, the the following three questions are the best predictors of a successful relationship (with successful couples generally answering the same way):

I meant just races in general, none in particular
maybe races isn't a good example. How about a very kind muslim and some stupid guy who thinks all muslims are terrorists and deserve to die? (no offence to any muslims by the way this is just an example, i'm not racist in any way)

Like Spock's Socks (PRSOM ) says I think it can work as long as you agree on the main things; marriage,money and kids.
There's not many minor differences between us, just our beliefs on the afterlife and our feelings towards violent film and tv mainly off the top of my head (he loves the walking dead for example and I hate it, but I ve always made the conscious effort to watch one episode of something he likes to try and compromise but that was too far)